src/fastcgi.h is referring to some "LICENSE.TERMS" that does not seem to be included in the source package. Can you clarify which one applies here? Ideally, that clarification would be put into the file directly for future reference.

History

Depending on your operating system distribution, documentation such as license files are included in the packages which provide the FCGI library or development headers. On Fedora Linux, LICENSE.TERMS is provided in the fcgi package, even though fastcgi.h is provided in the fcgi-devel package.

lighttpd implements the FastCGI protocol inside lighttpd mod_fastcgi, and includes fastcgi.h for the data structures and defines. The public interfaces (not the implementation) to a protocol exist to allow for other implementations to be written. I am not a language lawyer, so please do your own due diligence.

The lighttpd tests/fcgi-auth.c and tests/fcgi-responder.c test programs do rely on libfcgi and LICENSE.TERMS definitely applies to libfcgi. libfcgi is not distributed with lighttpd source.

The fcgi and fcgi-devel packages in Fedora Linux have the Open Market License (OML)